Nitrogen fertilizers are available in a myriad of forms.
In general they can be differentiated into simple water-soluble molecules which are essentially immediately available to plants, such as ammonia and nitrates, and those which exhibit a more or less controlled rate of dissolution (availability). R. D. Nauck in "Slow-Release and Bioinihibitor-Amended Nitrogen Fertilizers", in USA Fertilizer Technology and Use (3rd Edition), Soil Science Society of America, 677 South Segoe Road, Madison, Wisc. 53711 at page 293 states "One approach to increasing the efficiency of N fertilizer use by plants is to control the rate of N-fertilizer dissolution. This can be done by (i) developing compounds with limited water solubility and (ii) modifying water-soluble materials to delay release of their contained N to the soil solution."
Carbohydrate acid amides are known compounds and polymers which may be prepared by a number of methods. Preparation of gluconamides and glucaramides are described in D. E. Kiely, J. L. Navia, L. Miller and T-H. Lin, J. Carbohydr. Chem., 5, 183 (1986) and references therein. Preparation of N-alkylglucaramides is described in F. Schneider and H-U. Geyer, Tenside, 4, No 10, 330 (1967). Methods for preparing N,N'-dialkylglucaramides may be found in R. W. Kane, Ph.D. dissertation, University of Alabama at Birmingham, 1992 and references therein. The preparations of additional N,N'-dialkylaldaramides are also described in that reference. Preparation of poly(alkylene aldaramides) is disclosed in Kiely and Lin, U.S. Pat. No. 4,833,230, May 25, 1989. Preparation of poly(heteroalkylene aldaramides), polyamides of aldaric acids, in particular glucaric acid, in which heteroatoms, such as nitrogen or oxygen, are connecting atoms in the alkylenediamine chain, are disclosed in copending U.S. patent applications Ser. No.07/927,913, Aug. 12, 1992 and Kiely et al., "Polyaldaramide Polymers Useful for Films and Adhesives", and "Charged Polyaldaramide Polymers", both filed May 24, 1994.